Life-history genes in fishes: bridging functional and evolutionary genetics for understanding life-history trait evolution

Introduction

Life history is one of the most central concepts in biology. Numerous biological questions ultimately revolve around the causes and consequences of variation in reproduction and survival, i.e., fitness. Tremendous effort has been put into establishing the causes and mechanisms for life history trait variation and trade-offs.

Challenges in Research

Even in well-studied model organisms, evolutionary genetic and functional genomic approaches are rarely combined. Thus, the path from genotype to phenotype often remains a black box. A strategy to overcome this major hurdle has recently emerged, with the discovery of loci that explain exceptionally large proportions of the variation in various life history traits.

Opportunities with Life-History Genes

These “life-history genes” offer new opportunities to study not just the why (evolution) but also the how (functional genetics) of life history trait variation. I will address critical outstanding questions by bridging functional and evolutionary genetics approaches to study multiple loci linked with life-history traits including:

1. Age at maturity
2. Migration timing
3. Migration strategy

This research will focus on three fish species: Atlantic salmon, Rainbow trout/steelhead, and Atlantic cod.

Unique Research Potential

The relatively simple genetic architecture of the traits, combined with the features of these species as model systems, offers a unique opportunity to finally reveal the genetic architectures, molecular mechanisms, and ecological drivers that translate large-effect genotypes into adapted life history phenotypes. Additionally, it will examine how evolution shapes these processes.

Objectives of FishLEGs

In FishLEGs, I will:

i) Characterize the molecular functions behind genotype-life history associations;
ii) Elucidate life history trait reaction norms and evolution in variable environments;
iii) Determine the strength of natural and sexual selection on life history traits, their sex-specific effects, and model the evolutionary consequences.

Societal Relevance

Life history research also has societal relevance for health, sustainable fisheries, conservation, and climate resilience.